This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Nanoscale self-aggregation of proteins in biopolyelectrolyte solutions and on biopolyelectrolyte surface has received considerable attention in recent years due to tremendous scientific and technological implications, ranging from drug/food delivery systems to nanoscale biosensors. However, many issues related to the relationship among structure, rheological properties, chemical composition of the complexes formed by proteins and biopolyelectrolytes, as well as their intermolecular interactions are not clear, especially in the presence of specific binding ions, such as K+, Cs+, and Ca2+ etc. Our overall research goal is to establish a clear relationship among structure, rheological properties, and chemical composition. As part of our overall research goal, in this specific proposed research, we expect to study effects of physicochemical parameters, such as pH, ionic strength, protein/polyelectrolyte ratio, type of proteins (beta-lactoglobulin vs. beef gelatin and fish gelatin) on the structure of complexes formed by proteins and biopolyelectrolytes, such as alginate with different functional groups, pectin with different linear charge densities, chitosan of different molecular weights, and carboxymethyl cellulose (CMC).